diff --git a/.github/scripts/build_publish_payload.py b/.github/scripts/build_publish_payload.py
index 03cafd54..044f3903 100644
--- a/.github/scripts/build_publish_payload.py
+++ b/.github/scripts/build_publish_payload.py
@@ -127,6 +127,7 @@ def normalize_worker_interface(
     workers_json: dict[str, Any],
     functions_json: dict[str, Any],
     trigger_types_json: dict[str, Any] | None = None,
+    baseline_trigger_types_json: dict[str, Any] | None = None,
 ) -> dict[str, list[dict[str, Any]]]:
     workers = _extract_array(workers_json, "workers")
     worker = _match_worker(workers, worker_name)
@@ -162,12 +163,20 @@ def normalize_worker_interface(
             }
         )
 
+    baseline_ids = {
+        tt["id"]
+        for tt in _extract_array(baseline_trigger_types_json or {}, "trigger_types")
+        if isinstance(tt.get("id"), str)
+    }
+
     triggers = []
     if trigger_types_json:
         for trigger_type in _extract_array(trigger_types_json, "trigger_types"):
             tt_id = trigger_type.get("id")
             if not isinstance(tt_id, str) or tt_id.startswith("engine::"):
                 continue
+            if tt_id in baseline_ids:
+                continue
             triggers.append(_normalize_registry_trigger_type(trigger_type))
 
     return {"functions": functions, "triggers": triggers}
diff --git a/.github/scripts/collect_worker_interface.py b/.github/scripts/collect_worker_interface.py
index e2f2e877..21adf387 100644
--- a/.github/scripts/collect_worker_interface.py
+++ b/.github/scripts/collect_worker_interface.py
@@ -70,8 +70,15 @@ def main() -> int:
     parser.add_argument("--worker", required=True)
     parser.add_argument("--out", default="worker-interface.json")
     parser.add_argument("--wait-seconds", type=int, default=0)
+    parser.add_argument("--trigger-types-baseline", default="")
     args = parser.parse_args()
 
+    baseline_json = None
+    if args.trigger_types_baseline:
+        baseline_path = pathlib.Path(args.trigger_types_baseline)
+        if baseline_path.exists():
+            baseline_json = json.loads(baseline_path.read_text(encoding="utf-8"))
+
     workers_json = wait_for_worker(args.worker, args.wait_seconds)
     functions_json = run_iii("engine::functions::list", {"include_internal": True})
     trigger_types_json = collect_trigger_types()
@@ -81,6 +88,7 @@ def main() -> int:
         workers_json=workers_json,
         functions_json=functions_json,
         trigger_types_json=trigger_types_json,
+        baseline_trigger_types_json=baseline_json,
     )
     pathlib.Path(args.out).write_text(json.dumps(interface, indent=2) + "\n", encoding="utf-8")
     print(json.dumps(interface, indent=2))
diff --git a/.github/workflows/_publish-registry.yml b/.github/workflows/_publish-registry.yml
index 071e0ebf..49db51d9 100644
--- a/.github/workflows/_publish-registry.yml
+++ b/.github/workflows/_publish-registry.yml
@@ -93,6 +93,15 @@ jobs:
           cat iii-engine.log || true
           exit 1
 
+      - name: Snapshot engine trigger types baseline
+        run: |
+          set -euo pipefail
+          iii trigger \
+            --function-id='engine::trigger-types::list' \
+            --payload='{"include_internal": false}' \
+            > trigger-types-baseline.json
+          cat trigger-types-baseline.json
+
       - name: Start local worker for interface collection
         env:
           WORKER: ${{ inputs.worker }}
@@ -190,7 +199,12 @@ jobs:
         env:
           WORKER: ${{ inputs.worker }}
         run: |
-          args=("--worker" "$WORKER" "--out" "worker-interface.json" "--wait-seconds" "120")
+          args=(
+            "--worker" "$WORKER"
+            "--out" "worker-interface.json"
+            "--wait-seconds" "120"
+            "--trigger-types-baseline" "trigger-types-baseline.json"
+          )
           python3 .github/scripts/collect_worker_interface.py "${args[@]}"
 
       - name: Assert worker interface was collected